// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gfx/path_win.h"

#include <stddef.h>

#include <algorithm>
#include <vector>

#include "base/macros.h"
#include "base/win/scoped_gdi_object.h"
#include "skia/ext/skia_utils_win.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/skia/include/core/SkRRect.h"
#include "ui/gfx/path.h"

namespace gfx {

namespace {

    // Get rectangles from the |region| and convert them to SkIRect.
    std::vector<SkIRect> GetRectsFromHRGN(HRGN region)
    {
        // Determine the size of output buffer required to receive the region.
        DWORD bytes_size = GetRegionData(region, 0, NULL);
        CHECK_NE((DWORD)0, bytes_size);

        // Fetch the Windows RECTs that comprise the region.
        std::vector<char> buffer(bytes_size);
        LPRGNDATA region_data = reinterpret_cast<LPRGNDATA>(buffer.data());
        DWORD result = GetRegionData(region, bytes_size, region_data);
        CHECK_EQ(bytes_size, result);

        // Pull out the rectangles into a SkIRect vector to return to caller.
        const LPRECT rects = reinterpret_cast<LPRECT>(&region_data->Buffer[0]);
        std::vector<SkIRect> sk_rects(region_data->rdh.nCount);
        std::transform(rects, rects + region_data->rdh.nCount,
            sk_rects.begin(), skia::RECTToSkIRect);

        return sk_rects;
    }

} // namespace

// Test that rectangle with round corners stil has round corners after
// converting from SkPath to the HRGN.
// FIXME: this test is fragile (it depends on rrect rasterization impl)
TEST(CreateHRGNFromSkPathTest, RoundCornerTest)
{
    const SkIRect rects[] = {
        { 16, 0, 34, 1 },
        { 12, 1, 38, 2 },
        { 10, 2, 40, 3 },
        { 9, 3, 41, 4 },
        { 7, 4, 43, 5 },
        { 6, 5, 44, 6 },
        { 5, 6, 45, 7 },
        { 4, 7, 45, 8 },
        { 4, 8, 46, 9 },
        { 3, 9, 47, 10 },
        { 2, 10, 47, 11 },
        { 2, 11, 48, 12 },
        { 1, 12, 49, 16 },
        { 0, 16, 50, 34 },
        { 1, 34, 49, 38 },
        { 2, 38, 48, 39 },
        { 2, 39, 47, 40 },
        { 3, 40, 47, 41 },
        { 4, 41, 46, 42 },
        { 4, 42, 45, 43 },
        { 5, 43, 45, 44 },
        { 6, 44, 44, 45 },
        { 8, 45, 42, 46 },
        { 9, 46, 41, 47 },
        { 11, 47, 39, 48 },
        { 12, 48, 38, 49 },
        { 16, 49, 34, 50 },
    };

    Path path;
    SkRRect rrect;
    rrect.setRectXY(SkRect::MakeWH(50, 50), 20, 20);
    path.addRRect(rrect);
    base::win::ScopedRegion region(CreateHRGNFromSkPath(path));
    const std::vector<SkIRect>& region_rects = GetRectsFromHRGN(region.get());
    EXPECT_EQ(arraysize(rects), region_rects.size());
    for (size_t i = 0; i < arraysize(rects) && i < region_rects.size(); ++i)
        EXPECT_EQ(rects[i], region_rects[i]);
}

// Check that a path enclosing two non-adjacent areas is correctly translated
// to a non-contiguous region.
TEST(CreateHRGNFromSkPathTest, NonContiguousPath)
{
    const SkIRect rects[] = {
        { 0, 0, 50, 50 },
        { 100, 100, 150, 150 },
    };

    Path path;
    for (const SkIRect& rect : rects) {
        path.addRect(SkRect::Make(rect));
    }
    base::win::ScopedRegion region(CreateHRGNFromSkPath(path));
    const std::vector<SkIRect>& region_rects = GetRectsFromHRGN(region.get());
    ASSERT_EQ(arraysize(rects), region_rects.size());
    for (size_t i = 0; i < arraysize(rects); ++i)
        EXPECT_EQ(rects[i], region_rects[i]);
}

// Check that empty region is returned for empty path.
TEST(CreateHRGNFromSkPathTest, EmptyPath)
{
    Path path;
    base::win::ScopedRegion empty_region(::CreateRectRgn(0, 0, 0, 0));
    base::win::ScopedRegion region(CreateHRGNFromSkPath(path));
    EXPECT_TRUE(::EqualRgn(empty_region.get(), region.get()));
}

} // namespace gfx
